Interlocking control of a plurality of testing units



F. N. REEVES Filed May l5, 1924 INTRLOCKING CONTROL OF A PLURALITY OF TESTING UNITS July 20, 1926.

Patented July 20, 1926.

PATENT OFFICE.

UNITED STATES FRANK N. REEVES, F WOODENSBURG, MARYLAND, ASSIGNOR TO NVESTERN ELEC- TRIO COMPANY, INCORPORATED, GF NEW' YORK, N. Y., A CORPORATION OF NEW' Yoan.

INTERLOCKING CONTROL OF A PLURALITY OF TESTING UNITS.

Application filed May 13, 1924. Serial No. 712,826.

This invention relates to a telephone eX- change system, and more particularly to an interlocking control system for use 1n a teleplione ottice where a plurality of testing units are in simultaneous operation.

It is an object of this invention to provide means whereby test lines in a single group may be used by a plurality of like testing units in simultaneous operation.

In some machine switching oiiices, a large number of the' same. type of selective switches are used and since selective switches are made up of parts that require careful adjustment, it is important that they be regularly tested to maintain them in an operative condition at all times for completing service. connections. In otlices using i a large number of like selective switches it is desirable to use a pluralityof automatic routine testing units, each testing unit arranged to test a given number of the selective switches. f

The selective switches are directed under the control of each testing unit to a particular test line that is associated in operative relationship Awith the testing unit controlling the selective switch. From an economic basis, it is desirable to use only one group of bank multiple terminals for the test lines used by .all of said plurality of testing units. To eiect this economy it becomes necessary to use some means to prevent the simultaneous connection of more than one selective switch to any one of the test lines of said group and further to control the selection of a particular one of the test lines by the selective switch under test.

A feature of this invention is in the provision of interlocking control means to control the sequence of operation of a plurality of testing units and the selection of particular test lines in a single group of such lines.

This and other features of the invention will be apparent from the following description taken in connection with the accompanying drawin'g.

While the invention has been disclosed as particularly adapted for testing apparatus of a panel type machine switching otlice, it is apparent from the following description that the invention has a wider utility and that by slight modifications it could be adapted for testing other types of apparatus.

A single drawing accompanying this specification illustrates a plurality of testing units designated test set #1 and test set '#2, These test sets are similar in construction and operation and are described in detail in patent to E. F. Trapp, No. 1,544,958, dated July 7, 1925. A detailed description of the testing units will, therefore, not be made in this specification. The operation of selective switches 117 and 167 and the senders 118 and 168 are the same as described in the aforementioned patent. The test lines 1 and 2 are located in a single group of Test set #l and test set #-2 are automatic routine testing units for testing selective switches. Let it be assumed that these selective switches are of the type commonly known as districts that are controlled by senders. The selective switches may be divided into groups, the. switches kof each group being tested by an associated testing unit. The test lines to which the selective switches are directed are in one group of the district multiple, Test line 1 is representedv by terminals 120, 121, and 122 and test'line 2 is represented by terminals 170, 171 and 172.

Let it be assumed that test sets #l and #-2 are both in operation and that test set #2 has seized selective switch 167 preparatory to directing it to test line 2. During the operation of test set #2, the Sequence switch 150 shown therein is rotated to position 7 Let it further be assumed that test set #l has seized selective switch 117 preparatory to directing it to test line 1 but that the Sequence switch of test set #l has not rotated to position 7. In position 7 of the sequence switch 150 of test set #:2 a circuit is established to operate relay 160 lpreparatory to the establishment of circuits for control of the test lines. The circuit to operate relay 160 may be traced trom ground through its winding, contact ot cam 151 to grounded battery. The operation of relay 166 established a circuit to operate relay 162 from grounded battery through its winding, conductor 114, left contact of relay 112, conductor 113 to ground through the contact ci relay 160. The operation ot relay 162 establishes a circuit to characterize testline 1 as busy, from ground through the left inner contact of relay 162 to terminal 122. The operation of relay 162 opens at its left outer contact the circuit path over which relay 112 would normally be operate inthe rfunctioning ot test set 55:1. The oper` .ation of relay 162 further establishes a circuit to energize magnet 150 o1" the sequence switch, Vtest set #2. This circuit may be traced from grounded battery through the winding of magnet 150, contact of cam 155, right continuit-y contact `et relay 162 to ground through the contact ot relay 160 or to ground through the normal contact ot relay 161. Upon the rotation ot the sequence switch, the actuating circuit for relay 160 is opened at cam 151 to cause its release. The release of relay 160 opens the original actuating circuit for Vrelay 162 a holding .circuit for this relay is however maintained from ground through thernormal Contact of relay 161, right contact of relay 162, left contact of relay 112, lto ygrounded battery through the winding of relay 162. 4 Since the energizing circuit for sequence switch magnet 100, test set #1 for advancing it out of position 7, is only established when relay 112 is in an operated position, it is apparent that if the test set :#:1 Ashould rotate the sequence switch into position 7, the circuit for the further rotation of the sequence switch could not ybe established until relay 162 has released.

The selective `switch 167 is now controlled by test set #2 and the Vsender to direct it to the group of test lines containing test lines 1 and 2. Brushes 173, 174 and 17 5 of selective switch 167 are first brought into contact with test line 1. Since kthe sleeve terminal 122 of test line 1 is characterized as busy by the ground potential from the lett inner' contact of relay 162, a circuit is established over brush 175v to actuate the updrive magnet of selective switch 167 to cause its advance to test line` 2. The energization of the updrive magnet in v,this manner causes the selective switch to hunt for la trunk in the well known manner of operation for selective switches of this type and willl not be described further. lVhen the selective switch is advanced to test line 2 it is arrested in its upward movement since the sleeve terminal 172 is not characterized by a busy ground.

When brushes173, 174 and 17 5 are positioned upon theterminals ot test line 2, the

the test set 171:2 has advanced its sequence switch to position 11 in the manner described in the aforementioned patent to E. F. Trapp. lhen the selective switch 164 has advanced Vits sequence switch to talking position, a.

circuit established through its sequence switch contacts to operate relay 161 oi the test set. This circuit may be traced from grounded battery tl rough the winding ot relay 161, contact oit cam 154, 'conductor 158, terminal 170, brush 173, contact ot cam 178, winding of polarized relay 176, contact ot cam 17 7. brush 17d, terminal 171, conductor 157, cont-actor' cam 153 to ground. The operation ot relay 161 opens the holding circuit or relay 162 to cause its release, the ground at the contact of relay 160 having been removed due to the release ot relay 166 when sequence switch 150 advanced out o'l position 71,/2.

Let it be assumed that test set itl'lias advanced its sequence switch to position 7 and thatl its progression has been arrested. In position 7 an obvious circuit is established to operate relay 110. Upon the release of relay 162, circuit is established to operate relay 112. This .circuit may be traced irom grounded battery through its winding, conductor 115, lett outer normal Contact ot relay 162, conductor 116 to ground through contact or relay 110. A holding circuit is established for relay 112 over a circuit traced through its right contact to ground through the normal contact ot relay 111. rhe operation of relay 112 also` establishes a. circuit to actuate sequence switch magnet from grounded battery through its winding, contact of cam to ground through the contact of relay 11'() or to ground through the normal contact oi relay 111. The sequence switch of test set i'c1 is now advanced 'from position to position to control its local circuits and to control the selective switch 117. Under this control along with the control ot vthe sender, the selective switch is directed to the group or test lines containing test lines 1 and 2. When brushes 123, 12st and 125 are brought into contact with terminals 120, 121 and 122 of test line 1, the upward movement ot the selective switch is arrested since terminal122 is not characterized as busy by ground potential. The release oit the hunting` apparatus in the selective switch establishes circuits to rotate the sequence switch oll the selective switch into the talking position and at this time the sequence switch of test line 1 is arrested in position 11. A circuit is now established to energize relay 111 from grounded battery, through its winding, contact ci cam 104, conductor 10S,

`terminal 120, brushf123, contact of cam 128,

winding of polarized relay 126, contact of cam 127, brush 124, terminal 121, conductor 107, contact of cam 103 to ground. The operation of relay 111 opens the holding circuit for relay 112 to cause its release, the circuit of relay 110 having been previously opened at cam 101 when sequence switch 1. In a testing system arranged to directselective switches to the first line in a group of test lines, said switches being of a type that hunt an idle line in a group ofrlines, a. plurality of test lines in a single group, a plurality of testing units each operating as a. part ofsaid testing system to direct particular ones of said selective switches to said single group of test lines, and means controlled by each testing unit to cause the selective switch associated therewith to be connected to a particular one of said test lines. l

2. In a testing system arranged to direct selective switches to the first line in a group of test lines, said switches being of a typeV that hunt an idle line in a group of lines, a plurality of test lines in a single group, a plurality of testing units each operating as a part of said testing system to direct particular ones of said selective switches to said single group of test lines, and interlocking control means for the control of said plurality of testing units to successively direct associated selective switches to particular ones of said test lines.

3. In a testing system arranged to direct selective switches to the first line in a group of test lines, said switches being of a type that hunt an idle line in a group of lines, a plurality of test lines in a single group, a plurality of testing units each operating as a part of said testing system to direct particular ones of said selective switches to said single group of test lines, means controlled by each testing unit to cause the selective switch associated therewith to be connected to a particular one of said test lines, and mea-ns whereby each testing unit may control each other such testing unit in a manner to prevent simultaneous connection of a plurality of selective switches to one test line.

1. In a testing system arranged to direct selective switches to the first line in a group of test lines, said switches being of a type that hunt an idle line in a group of lines, a plurality or" test lines in a single group, a testing unit operated as a part of said system to direct such switches toA said test lines, a--second testing unit operated as a part of said system to direct other of such switches to said test lines, and means to prevent said second testing unit from directing an associated switch to a test line during the time said first testing unit is directing an associated switch to a'test line.

5. In a testing system arranged to direct selective switches to the first line in a group of test lines, said switches being of a type that hunt an idle line in a group of lines, a plurality of testlines in a single group, a testing unit operated as a part of said system to direct such switches to said testlines, a second testing unit operated as a part of said system to direct other of such switches to said test lines, means to prevent said second testing unit from directing an associated switch to a test line during the time said first testing unit is directing an associated switch to a test line, and means to cause the selective switch associated with said first testing unit to select a test line other than the first test line of said Single group.

6. In a testing system arranged to direct selective switches to the first line in a group of test lines. said switches' being of a type that hunt an idle line in a group of lines, a plurality of test lines in a single group, a testing unit operated as a part of said system to direct such switches to said test lines, a second testing unit operated as a part of: said system to direct other of such switches to said test lines, means to prevent said second testing' unit from directing an associated switch to a test line during the time said first testing unit is directing an associated switch to a test line, means to cause the selective switch associated with said first testing unit to select a test line other than the first test line of said single group, and means operative when said other test line has been selected to establish a condition whereby said second testing unit may function for directing a selective switch to a test line of said single group.

7. In combination, a plurality of' selective switches of a type that hunt an idle line in a group of lines, a plurality of lines in a single group, a plurality of automatically progressive contrcl units each operating to direct said selective switches to said single group of lines, and interlocking control means to regulate the selection of a particular line in said single group by a particular selective switch.

8. In combination, a plurality of selective switches of a type that hunt an idle line in a group of lines, a plurality of lines in a single group, a plurality of automatically progressive control units eacli yoperating to direct said selective switches 'to said singlegroup of lines, and interlocking control means to regulate the progression of saidrcontrol units and the selection ot' a particular line in said single group by a particular selective switch.

9. In combination, a plurality of selective switches of a type that liunt an idle line in a group of lines, a plurality of lines in a single group, a plurality of automatically progressive control units each operating to direct said selective switches to said single group of lines` and interlocking control means to regulate the progression ot said control units, and the selection of particular lines in said single group by selective switches associated with particular ones or said control units.

l0. In combination. a plurality7 of selective .switches of a type 'that hunt an idle line in a ciated therewith to be connected to a particular one of `said lines.

In Witness Wlicreoi, hereunto subscribe my name this 9th day of May A. D., 192i.

FRANK N. REEVES. 

